Candidates write and run code in a browser editor, in the language they use at work. Goodfit runs hidden test cases on each submission and saves every run along the way. Your engineers only interview people whose code works.
Backend Engineer Test · Ranked by score
36 of 50 invited have finished
Wei Zhang
Arrays 100% · Hash maps 90% · SQL 80% · Recursion 70%
Emily Carter
Arrays 90% · Hash maps 80% · SQL 70% · Recursion 40%
Marco Rossi
Arrays 80% · Hash maps 60% · SQL 70% · Recursion 50%
Aisha Bello
Arrays 60% · Hash maps 40% · SQL 50% · Recursion 10%
Trusted by HR teams at 300+ companies
An engineer gives up an hour for each interview, and many candidates cannot solve a basic problem.
Five years of Python on a resume does not tell you whether someone can write a working function.
A task done over a weekend may be the work of a friend or an AI tool. You cannot see how it was written.
Each first-round interview takes an engineer away from their own work for an hour. Most of those hours go to people who cannot pass a basic problem.
Candidates open the test from a link and code in a browser editor. They pick from the languages you allow and run their work against the public examples, with the real output and any error messages. A timer shows the time left for each problem. After they submit, they see how many hidden tests passed, but never the hidden inputs.
merge_bookings.py
Python 3 ▾ · Problem 1 of 4 · 6:10 left
1def merge(bookings):2 bookings.sort(key=lambda b: b[0])3 merged = [bookings[0]]4 for start, end in bookings[1:]:5 if start <= merged[-1][1]:6 merged[-1][1] = max(merged[-1][1], end)7 else:8 merged.append([start, end])9 return merged
The library covers algorithms, data structures, SQL, Bash and PySpark at easy, medium and hard levels. Goodfit suggests problems that match the job you are hiring for. You can also write problems for your own stack, with your own test cases.
Problem library
Suggested for Backend Engineer (Python, REST APIs, SQL)
Library · 12 ready-made sets · Your problems
While they work, candidates test their code on the public examples. When they submit, Goodfit runs it on hidden test cases. A copied answer that handles the easy case fails the tricky ones. Each problem earns credit for every hidden test passed, so you can tell a near miss from code that never worked.
Submission · Rate limiter for an API
Emily Carter · Python · Problem 2 of 4
Credit for this problem: 8 of 10 hidden tests = 80%
Each problem is tagged to a skill, like arrays, SQL joins or recursion. The report adds up the credit by skill. Before the interview, a hiring manager can see that a candidate handles data well and struggles with recursion.
Emily Carter
Backend Engineer Test · 4 problems
Overall 70% is the average of the four skills · pass mark 65%
You can step through every run and submission in order. A diff shows what changed since the last run, the first run or the final answer. You see who worked through the bug and who had a full answer in one step.
Run history · Merge overlapping bookings
Emily Carter · Python · 15-minute timer
Run 1
0/3 examples03:14 · IndexError on line 3
Run 2
2/3 examples06:02 · Sorted the bookings first
Run 3
3/3 examples08:40
Submit 1
7/10 hidden09:15 · Missed bookings that touch
Submit 2
9/10 hidden12:31 · Final answer
You write the tables and the sample rows. The candidate sees the table definitions and writes a query. Goodfit runs it and compares the result with the columns and rows you expect. You decide whether row order matters.
top_customers.sql
Problem 3 of 4 · Run 2
1-- Your setup: 2 tables, 52 sample rows2-- customers(id, name)3-- orders(id, customer_id, amount, status)4SELECT c.name, SUM(o.amount) AS revenue5FROM customers c6JOIN orders o ON o.customer_id = c.id7WHERE o.status = 'paid'8GROUP BY c.name9ORDER BY revenue DESC10LIMIT 5;
Phone screens are blocked, so everyone codes on a proper screen. The test pauses if the candidate leaves fullscreen. Copy and paste are blocked in the editor, and each try is logged. Goodfit also checks the browser for AI assistant add-ons.
RecordingA warm-up might get 15 minutes and a harder problem 40. When a problem’s time runs out, the candidate moves to the next one. Some problems can go to everyone. Others are drawn at random by difficulty, so candidates get a different mix.
Test settings · Backend Engineer
4 problems per candidate
Languages allowed: Python, Java, Go and SQL
Free to start
Try Goodfit on your next open role
Create a free account, add a job and send the AI interview to real applicants. You get a scorecard for each one with the recording behind every score.
DBDaniel Brooks
Your first applicant · scored minutes after the AI interview
8.0 /10
“First I’d check the order, then call the customer back.” ▶ 02:14
“I stayed calm and told them exactly what I could do today.” ▶ 05:40
Start from a ready-made set like the backend screen, or choose from problems suggested for your job.
Choose the languages, timers, random draws and the pass mark.
Open the skill scores and run history for everyone above the pass mark.
Here is what HR teams say about Goodfit, and the results they saw.
“With Goodfit's coding assessments, we can evaluate candidates' technical skills much earlier in the hiring process. It helps us identify stronger candidates faster and makes the screening process much more efficient.”
Sakshi Srivastava
Campus Recruiter & Campus Relations, Xcelore
2,600+
AI interviews run, most of them on campus drives
An outside auditor checks our security. Your data is encrypted when stored and when sent.
Neither Goodfit nor our AI providers train models on your data.
Everyone is scored on the same rubric, and accent doesn’t count against anyone. Each score links to that moment in the recording.
People join by phone or from a browser link. There is nothing to download.
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Goodfit talks with applicants and employees by phone or in a browser. Try it on one of your open roles.
